Which TWO statements about crontab are true?
A. Every user may have their owncrontab.
B. Changing a crontab requires a reload/restart of the cron daemon.
C. The cron daemon reloads crontab files automatically when necessary.
D. hourly is the same as "0 * * * *".
E. A cron daemon must run for each existing crontab.
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Answer: A and D
Correct Answer: A+D
https://man7.org/linux/man-pages/man5/crontab.5.html
A crontab file contains instructions for the cron(8) daemon in
the following simplified manner: “run this command at this time
on this date”. Each user can define their own crontab. Commands
defined in any given crontab are executed under the user who owns
that particular crontab. Uucp and News usually have their own
crontabs, eliminating the need for explicitly running su(1) as
part of a cron command.
@hourly : Run once an hour, ie. “0 * * * *”.
CAVEATS top
crontab files have to be regular files or symlinks to regular
files, they must not be executable or writable for anyone else
but the owner. This requirement can be overridden by using the
-p option on the crond command line. If inotify support is in
use, changes in the symlinked crontabs are not automatically
noticed by the cron daemon. The cron daemon must receive a
SIGHUP signal to reload the crontabs. This is a limitation of
the inotify API.
cron requires that each entry in a crontab end in a newline
character. If the last entry in a crontab is missing a newline
(i.e. terminated by EOF), cron will consider the crontab (at
least partially) broken. A warning will be written to syslog.